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Tsirkin" , Jason Wang , Xuan Zhuo , Richard Cochran , netdev@vger.kernel.org, Marc Zyngier , Mark Rutland , Daniel Lezcano , Thomas Gleixner , linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v2 4/6] virtio_rtc: Add module and driver core Date: Fri, 18 Aug 2023 03:20:10 +0200 Message-Id: <20230818012014.212155-5-peter.hilber@opensynergy.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230818012014.212155-1-peter.hilber@opensynergy.com> References: <20230818012014.212155-1-peter.hilber@opensynergy.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: VI1EUR05FT068:EE_|FR2P281MB1718:EE_ X-MS-Office365-Filtering-Correlation-Id: 7ce4a7fc-21fe-4b28-befe-08db9f894dcd X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:217.66.60.4;CTRY:DE;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SR-MAIL-03.open-synergy.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230031)(136003)(396003)(376002)(346002)(39830400003)(186009)(82310400011)(1800799009)(451199024)(46966006)(36840700001)(66899024)(83380400001)(336012)(81166007)(86362001)(36756003)(47076005)(36860700001)(1076003)(40480700001)(26005)(2616005)(7416002)(8936002)(8676002)(4326008)(30864003)(41300700001)(54906003)(70206006)(70586007)(42186006)(2906002)(316002)(5660300002)(966005)(478600001)(12101799020)(44832011)(36900700001);DIR:OUT;SFP:1102; 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The virtio_rtc module implements a driver compatible with the proposed Virtio RTC device specification [1]. The Virtio RTC (Real Time Clock) device provides information about current time. The device can provide different clocks, e.g. for the UTC or TAI time standards, or for physical time elapsed since some past epoch. The driver can read the clocks with simple or more accurate methods. Implement the core, which interacts with the Virtio RTC device. Apart from this, the core does not expose functionality outside of the virtio_rtc module. A follow-up patch will expose PTP clocks. Provide synchronous messaging, which is enough for the expected time synchronization use cases through PTP clocks (similar to ptp_kvm) or RTC Class driver. [1] https://lists.oasis-open.org/archives/virtio-comment/202306/msg00592.html Signed-off-by: Peter Hilber --- MAINTAINERS | 7 + drivers/virtio/Kconfig | 14 + drivers/virtio/Makefile | 2 + drivers/virtio/virtio_rtc_driver.c | 736 +++++++++++++++++++++++++++ drivers/virtio/virtio_rtc_internal.h | 23 + include/uapi/linux/virtio_rtc.h | 159 ++++++ 6 files changed, 941 insertions(+) create mode 100644 drivers/virtio/virtio_rtc_driver.c create mode 100644 drivers/virtio/virtio_rtc_internal.h create mode 100644 include/uapi/linux/virtio_rtc.h diff --git a/MAINTAINERS b/MAINTAINERS index 11b470d38e3f..025c0f8fb7a6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -22841,6 +22841,13 @@ S: Maintained F: drivers/nvdimm/nd_virtio.c F: drivers/nvdimm/virtio_pmem.c +VIRTIO RTC DRIVER +M: Peter Hilber +L: virtualization@lists.linux-foundation.org +S: Maintained +F: drivers/virtio/virtio_rtc_* +F: include/uapi/linux/virtio_rtc.h + VIRTIO SOUND DRIVER M: Anton Yakovlev M: "Michael S. Tsirkin" diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 0a53a61231c2..e3dbf16fa977 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -173,4 +173,18 @@ config VIRTIO_DMA_SHARED_BUFFER This option adds a flavor of dma buffers that are backed by virtio resources. +config VIRTIO_RTC + tristate "Virtio RTC driver" + depends on VIRTIO + depends on PTP_1588_CLOCK_OPTIONAL + help + This driver provides current time from a Virtio RTC device. The driver + provides the time through one or more clocks. The driver sub-option + VIRTIO_RTC_PTP must be enabled to expose the clocks to userspace. + + To compile this code as a module, choose M here: the module will be + called virtio_rtc. + + If unsure, say M. + endif # VIRTIO_MENU diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index 8e98d24917cc..f760414ed6ab 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -12,3 +12,5 @@ obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o obj-$(CONFIG_VIRTIO_VDPA) += virtio_vdpa.o obj-$(CONFIG_VIRTIO_MEM) += virtio_mem.o obj-$(CONFIG_VIRTIO_DMA_SHARED_BUFFER) += virtio_dma_buf.o +obj-$(CONFIG_VIRTIO_RTC) += virtio_rtc.o +virtio_rtc-y := virtio_rtc_driver.o diff --git a/drivers/virtio/virtio_rtc_driver.c b/drivers/virtio/virtio_rtc_driver.c new file mode 100644 index 000000000000..424500d2c4f7 --- /dev/null +++ b/drivers/virtio/virtio_rtc_driver.c @@ -0,0 +1,736 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * virtio_rtc driver core + * + * Copyright (C) 2022-2023 OpenSynergy GmbH + */ + +#include +#include +#include +#include +#include + +#include + +#include "virtio_rtc_internal.h" + +/* virtqueue order */ +enum { + VIORTC_READQ, + VIORTC_CONTROLQ, + VIORTC_MAX_NR_QUEUES, +}; + +/** + * struct viortc_vq - virtqueue abstraction + * @vq: virtqueue + * @lock: protects access to vq + */ +struct viortc_vq { + struct virtqueue *vq; + spinlock_t lock; +}; + +/** + * struct viortc_dev - virtio_rtc device data + * @vdev: virtio device + * @vqs: virtqueues + * @num_clocks: # of virtio_rtc clocks + */ +struct viortc_dev { + struct virtio_device *vdev; + struct viortc_vq vqs[VIORTC_MAX_NR_QUEUES]; + u16 num_clocks; +}; + +/** + * struct viortc_msg - Message requested by driver, responded by device. + * @viortc: device data + * @req: request buffer + * @resp: response buffer + * @responded: vqueue callback signals response reception + * @refcnt: Message reference count, message and buffers will be deallocated + * once 0. refcnt is decremented in the vqueue callback and in the + * thread waiting on the responded completion. + * If a message response wait function times out, the message will be + * freed upon late reception (refcnt will reach 0 in the callback), or + * device removal. + * @req_size: size of request in bytes + * @resp_cap: maximum size of response in bytes + * @resp_actual_size: actual size of response + */ +struct viortc_msg { + struct viortc_dev *viortc; + void *req; + void *resp; + struct completion responded; + refcount_t refcnt; + unsigned int req_size; + unsigned int resp_cap; + unsigned int resp_actual_size; +}; + +/** + * viortc_msg_init() - Allocate and initialize message. + * @viortc: device data + * @msg_type: virtio_rtc message type + * @req_size: size of request buffer to be allocated + * @resp_cap: size of response buffer to be allocated + * + * Initializes the message refcnt to 2. The refcnt will be decremented once in + * the virtqueue callback, and once in the thread waiting on the message (on + * completion or timeout). + * + * Context: Process context. + * Return: non-NULL on success. + */ +static struct viortc_msg *viortc_msg_init(struct viortc_dev *viortc, + u16 msg_type, unsigned int req_size, + unsigned int resp_cap) +{ + struct viortc_msg *msg; + struct device *dev = &viortc->vdev->dev; + struct virtio_rtc_req_head *req_head; + + msg = devm_kzalloc(dev, sizeof(*msg), GFP_KERNEL); + if (!msg) + return NULL; + + init_completion(&msg->responded); + + msg->req = devm_kzalloc(dev, req_size, GFP_KERNEL); + if (!msg->req) + goto err_free_msg; + + req_head = msg->req; + + msg->resp = devm_kzalloc(dev, resp_cap, GFP_KERNEL); + if (!msg->resp) + goto err_free_msg_req; + + msg->viortc = viortc; + msg->req_size = req_size; + msg->resp_cap = resp_cap; + + refcount_set(&msg->refcnt, 2); + + req_head->msg_type = virtio_cpu_to_le(msg_type, req_head->msg_type); + + return msg; + +err_free_msg_req: + devm_kfree(dev, msg->req); + +err_free_msg: + devm_kfree(dev, msg); + + return NULL; +} + +/** + * viortc_msg_release() - Decrement message refcnt, potentially free message. + * @msg: message requested by driver + * + * Context: Any context. + */ +static void viortc_msg_release(struct viortc_msg *msg) +{ + if (refcount_dec_and_test(&msg->refcnt)) { + struct device *dev = &msg->viortc->vdev->dev; + + devm_kfree(dev, msg->req); + devm_kfree(dev, msg->resp); + devm_kfree(dev, msg); + } +} + +/** + * viortc_cb() - callback for readq and controlq + * @vq: virtqueue with device response + * + * Signals completion for each received message. + * + * Context: virtqueue callback, typically interrupt. Takes and releases vq lock. + */ +static void viortc_cb(struct virtqueue *vq) +{ + struct viortc_dev *viortc = vq->vdev->priv; + spinlock_t *lock = &viortc->vqs[vq->index].lock; + unsigned long flags; + struct viortc_msg *msg; + unsigned int len; + bool cb_enabled = true; + + for (;;) { + spin_lock_irqsave(lock, flags); + + if (cb_enabled) { + virtqueue_disable_cb(vq); + cb_enabled = false; + } + + msg = virtqueue_get_buf(vq, &len); + if (!msg) { + if (virtqueue_enable_cb(vq)) { + spin_unlock_irqrestore(lock, flags); + return; + } + cb_enabled = true; + } + + spin_unlock_irqrestore(lock, flags); + + if (msg) { + msg->resp_actual_size = len; + + /* + * completion waiter must see our msg metadata, but + * complete() does not guarantee a memory barrier + */ + smp_wmb(); + + complete(&msg->responded); + viortc_msg_release(msg); + } + } +} + +/** + * viortc_get_resp_errno() - converts virtio_rtc errnos to system errnos + * @resp_head: message response header + * + * Return: negative system errno, or 0 + */ +static int viortc_get_resp_errno(struct virtio_rtc_resp_head *resp_head) +{ + switch (virtio_le_to_cpu(resp_head->status)) { + case VIRTIO_RTC_S_OK: + return 0; + case VIRTIO_RTC_S_UNSUPP: + return -EOPNOTSUPP; + case VIRTIO_RTC_S_INVAL: + return -EINVAL; + case VIRTIO_RTC_S_NODEV: + return -ENODEV; + case VIRTIO_RTC_S_DEVERR: + default: + return -EIO; + } +} + +/** + * viortc_msg_xfer() - send message request, wait until message response + * @vq: virtqueue + * @msg: message with driver request + * @timeout_jiffies: message response timeout, 0 for no timeout + * + * Context: Process context. Takes and releases vq.lock. May sleep. + */ +static int viortc_msg_xfer(struct viortc_vq *vq, struct viortc_msg *msg, + unsigned long timeout_jiffies) +{ + int ret; + unsigned long flags; + struct scatterlist out_sg[1]; + struct scatterlist in_sg[1]; + struct scatterlist *sgs[2] = { out_sg, in_sg }; + bool notify; + + sg_init_one(out_sg, msg->req, msg->req_size); + sg_init_one(in_sg, msg->resp, msg->resp_cap); + + spin_lock_irqsave(&vq->lock, flags); + + ret = virtqueue_add_sgs(vq->vq, sgs, 1, 1, msg, GFP_ATOMIC); + if (ret) { + spin_unlock_irqrestore(&vq->lock, flags); + /* + * Release in place of the response callback, which will never + * come. + */ + viortc_msg_release(msg); + return ret; + } + + notify = virtqueue_kick_prepare(vq->vq); + + spin_unlock_irqrestore(&vq->lock, flags); + + if (notify) + virtqueue_notify(vq->vq); + + if (timeout_jiffies) { + long timeout_ret; + + timeout_ret = wait_for_completion_interruptible_timeout( + &msg->responded, timeout_jiffies); + + if (!timeout_ret) + return -ETIMEDOUT; + else if (timeout_ret < 0) + return (int)timeout_ret; + } else { + ret = wait_for_completion_interruptible(&msg->responded); + if (ret) + return ret; + } + + /* + * Ensure we can read message metadata written in the virtqueue + * callback. + */ + smp_rmb(); + + /* + * There is not yet a case where returning a short message would make + * sense, so consider any deviation an error. + */ + if (msg->resp_actual_size != msg->resp_cap) + return -EINVAL; + + return viortc_get_resp_errno(msg->resp); +} + +/* + * common message handle macros for messages of different types + */ + +/** + * VIORTC_DECLARE_MSG_HDL_ONSTACK() - declare message handle on stack + * @hdl: message handle name + * @msg_suf_lowerc: message type suffix in lowercase + * @msg_suf_upperc: message type suffix in uppercase + */ +#define VIORTC_DECLARE_MSG_HDL_ONSTACK(hdl, msg_suf_lowerc, msg_suf_upperc) \ + struct { \ + struct viortc_msg *msg; \ + struct virtio_rtc_req_##msg_suf_lowerc *req; \ + struct virtio_rtc_resp_##msg_suf_lowerc *resp; \ + unsigned int req_size; \ + unsigned int resp_cap; \ + u16 msg_type; \ + } hdl = { \ + NULL, \ + NULL, \ + NULL, \ + sizeof(struct virtio_rtc_req_##msg_suf_lowerc), \ + sizeof(struct virtio_rtc_resp_##msg_suf_lowerc), \ + VIRTIO_RTC_M_##msg_suf_upperc, \ + } + +/** + * VIORTC_MSG() - extract message from message handle + * + * Return: struct viortc_msg + */ +#define VIORTC_MSG(hdl) ((hdl).msg) + +/** + * VIORTC_MSG_INIT() - initialize message handle + * @hdl: message handle + * @viortc: device data (struct viortc_dev *) + * + * Context: Process context. + * Return: 0 on success, -ENOMEM otherwise. + */ +#define VIORTC_MSG_INIT(hdl, viortc) \ + ({ \ + typeof(hdl) *_hdl = &(hdl); \ + \ + _hdl->msg = viortc_msg_init((viortc), _hdl->msg_type, \ + _hdl->req_size, _hdl->resp_cap); \ + if (_hdl->msg) { \ + _hdl->req = _hdl->msg->req; \ + _hdl->resp = _hdl->msg->resp; \ + } \ + _hdl->msg ? 0 : -ENOMEM; \ + }) + +/** + * VIORTC_MSG_WRITE() - write a request message field + * @hdl: message handle + * @dest_member: request message field name + * @src_ptr: pointer to data of compatible type + * + * Writes the field in little-endian format. + */ +#define VIORTC_MSG_WRITE(hdl, dest_member, src_ptr) \ + do { \ + typeof(hdl) _hdl = (hdl); \ + typeof(src_ptr) _src_ptr = (src_ptr); \ + \ + /* Sanity check: must match the member's type */ \ + typecheck(typeof(_hdl.req->dest_member), *_src_ptr); \ + \ + _hdl.req->dest_member = \ + virtio_cpu_to_le(*_src_ptr, _hdl.req->dest_member); \ + } while (0) + +/** + * VIORTC_MSG_READ() - read from a response message field + * @hdl: message handle + * @src_member: response message field name + * @dest_ptr: pointer to data of compatible type + * + * Converts from little-endian format and writes to dest_ptr. + */ +#define VIORTC_MSG_READ(hdl, src_member, dest_ptr) \ + do { \ + typeof(dest_ptr) _dest_ptr = (dest_ptr); \ + \ + /* Sanity check: must match the member's type */ \ + typecheck(typeof((hdl).resp->src_member), *_dest_ptr); \ + \ + *_dest_ptr = virtio_le_to_cpu((hdl).resp->src_member); \ + } while (0) + +/* + * readq messages + */ + +/** timeout for clock readings, where timeouts are considered non-fatal */ +#define VIORTC_MSG_READ_TIMEOUT (msecs_to_jiffies(60 * 1000)) + +/** + * viortc_read() - VIRTIO_RTC_M_READ message wrapper + * @viortc: device data + * @vio_clk_id: virtio_rtc clock id + * @reading: clock reading [ns] + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +int viortc_read(struct viortc_dev *viortc, u64 vio_clk_id, u64 *reading) +{ + int ret; + VIORTC_DECLARE_MSG_HDL_ONSTACK(hdl, read, READ); + + ret = VIORTC_MSG_INIT(hdl, viortc); + if (ret) + return ret; + + VIORTC_MSG_WRITE(hdl, clock_id, &vio_clk_id); + + ret = viortc_msg_xfer(&viortc->vqs[VIORTC_READQ], VIORTC_MSG(hdl), + VIORTC_MSG_READ_TIMEOUT); + if (ret) { + dev_dbg(&viortc->vdev->dev, "%s: xfer returned %d\n", __func__, + ret); + goto out_release; + } + + VIORTC_MSG_READ(hdl, clock_reading, reading); + +out_release: + viortc_msg_release(VIORTC_MSG(hdl)); + + return ret; +} + +/** + * viortc_read_cross() - VIRTIO_RTC_M_READ_CROSS message wrapper + * @viortc: device data + * @vio_clk_id: virtio_rtc clock id + * @hw_counter: virtio_rtc HW counter type + * @reading: clock reading [ns] + * @cycles: HW counter cycles during clock reading + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +int viortc_read_cross(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, + u64 *reading, u64 *cycles) +{ + int ret; + VIORTC_DECLARE_MSG_HDL_ONSTACK(hdl, read_cross, READ_CROSS); + + ret = VIORTC_MSG_INIT(hdl, viortc); + if (ret) + return ret; + + VIORTC_MSG_WRITE(hdl, clock_id, &vio_clk_id); + VIORTC_MSG_WRITE(hdl, hw_counter, &hw_counter); + + ret = viortc_msg_xfer(&viortc->vqs[VIORTC_READQ], VIORTC_MSG(hdl), + VIORTC_MSG_READ_TIMEOUT); + if (ret) { + dev_dbg(&viortc->vdev->dev, "%s: xfer returned %d\n", __func__, + ret); + goto out_release; + } + + VIORTC_MSG_READ(hdl, clock_reading, reading); + VIORTC_MSG_READ(hdl, counter_cycles, cycles); + +out_release: + viortc_msg_release(VIORTC_MSG(hdl)); + + return ret; +} + +/* + * controlq messages + */ + +/** + * viortc_cfg() - VIRTIO_RTC_M_CFG message wrapper + * @viortc: device data + * @num_clocks: # of virtio_rtc clocks + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_cfg(struct viortc_dev *viortc, u16 *num_clocks) +{ + int ret; + VIORTC_DECLARE_MSG_HDL_ONSTACK(hdl, cfg, CFG); + + ret = VIORTC_MSG_INIT(hdl, viortc); + if (ret) + return ret; + + ret = viortc_msg_xfer(&viortc->vqs[VIORTC_CONTROLQ], VIORTC_MSG(hdl), + 0); + if (ret) { + dev_dbg(&viortc->vdev->dev, "%s: xfer returned %d\n", __func__, + ret); + goto out_release; + } + + VIORTC_MSG_READ(hdl, num_clocks, num_clocks); + +out_release: + viortc_msg_release(VIORTC_MSG(hdl)); + + return ret; +} + +/** + * viortc_clock_cap() - VIRTIO_RTC_M_CLOCK_CAP message wrapper + * @viortc: device data + * @vio_clk_id: virtio_rtc clock id + * @type: virtio_rtc clock type + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_clock_cap(struct viortc_dev *viortc, u64 vio_clk_id, + u16 *type) +{ + int ret; + VIORTC_DECLARE_MSG_HDL_ONSTACK(hdl, clock_cap, CLOCK_CAP); + + ret = VIORTC_MSG_INIT(hdl, viortc); + if (ret) + return ret; + + VIORTC_MSG_WRITE(hdl, clock_id, &vio_clk_id); + + ret = viortc_msg_xfer(&viortc->vqs[VIORTC_CONTROLQ], VIORTC_MSG(hdl), + 0); + if (ret) { + dev_dbg(&viortc->vdev->dev, "%s: xfer returned %d\n", __func__, + ret); + goto out_release; + } + + VIORTC_MSG_READ(hdl, type, type); + +out_release: + viortc_msg_release(VIORTC_MSG(hdl)); + + return ret; +} + +/** + * viortc_cross_cap() - VIRTIO_RTC_M_CROSS_CAP message wrapper + * @viortc: device data + * @vio_clk_id: virtio_rtc clock id + * @hw_counter: virtio_rtc HW counter type + * @supported: xtstamping is supported for the vio_clk_id/hw_counter pair + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +int viortc_cross_cap(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, + bool *supported) +{ + int ret; + VIORTC_DECLARE_MSG_HDL_ONSTACK(hdl, cross_cap, CROSS_CAP); + u8 flags; + + ret = VIORTC_MSG_INIT(hdl, viortc); + if (ret) + return ret; + + VIORTC_MSG_WRITE(hdl, clock_id, &vio_clk_id); + VIORTC_MSG_WRITE(hdl, hw_counter, &hw_counter); + + ret = viortc_msg_xfer(&viortc->vqs[VIORTC_CONTROLQ], VIORTC_MSG(hdl), + 0); + if (ret) { + dev_dbg(&viortc->vdev->dev, "%s: xfer returned %d\n", __func__, + ret); + goto out_release; + } + + VIORTC_MSG_READ(hdl, flags, &flags); + *supported = !!(flags & BIT(VIRTIO_RTC_FLAG_CROSS_CAP)); + +out_release: + viortc_msg_release(VIORTC_MSG(hdl)); + + return ret; +} + +/* + * init, deinit + */ + +/** + * viortc_clocks_init() - init local representations of virtio_rtc clocks + * @viortc: device data + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_clocks_init(struct viortc_dev *viortc) +{ + int ret; + u16 num_clocks; + + ret = viortc_cfg(viortc, &num_clocks); + if (ret) + return ret; + + if (num_clocks < 1) { + dev_err(&viortc->vdev->dev, "device reported 0 clocks\n"); + return -ENODEV; + } + + viortc->num_clocks = num_clocks; + + /* In the future, PTP clocks will be initialized here. */ + (void)viortc_clock_cap; + + return 0; +} + +/** + * viortc_init_vqs() - init virtqueues + * @viortc: device data + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + * + * Init virtqueues, and their abstractions. + */ +static int viortc_init_vqs(struct viortc_dev *viortc) +{ + int ret; + struct virtio_device *vdev = viortc->vdev; + const char *names[VIORTC_MAX_NR_QUEUES]; + vq_callback_t *callbacks[VIORTC_MAX_NR_QUEUES]; + struct virtqueue *vqs[VIORTC_MAX_NR_QUEUES]; + int nr_queues; + + names[VIORTC_READQ] = "readq"; + callbacks[VIORTC_READQ] = viortc_cb; + + names[VIORTC_CONTROLQ] = "controlq"; + callbacks[VIORTC_CONTROLQ] = viortc_cb; + + nr_queues = 2; + + ret = virtio_find_vqs(vdev, nr_queues, vqs, callbacks, names, NULL); + if (ret) + return ret; + + viortc->vqs[VIORTC_READQ].vq = vqs[VIORTC_READQ]; + spin_lock_init(&viortc->vqs[VIORTC_READQ].lock); + + viortc->vqs[VIORTC_CONTROLQ].vq = vqs[VIORTC_CONTROLQ]; + spin_lock_init(&viortc->vqs[VIORTC_CONTROLQ].lock); + + return 0; +} + +/** + * viortc_probe() - probe a virtio_rtc virtio device + * @vdev: virtio device + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_probe(struct virtio_device *vdev) +{ + struct viortc_dev *viortc; + int ret; + + viortc = devm_kzalloc(&vdev->dev, sizeof(*viortc), GFP_KERNEL); + if (!viortc) + return -ENOMEM; + + vdev->priv = viortc; + viortc->vdev = vdev; + + ret = viortc_init_vqs(viortc); + if (ret) + return ret; + + virtio_device_ready(vdev); + + /* Ready vdev for use by frontend devices initialized next. */ + smp_wmb(); + + ret = viortc_clocks_init(viortc); + if (ret) + goto err_reset_vdev; + + return 0; + +err_reset_vdev: + virtio_reset_device(vdev); + vdev->config->del_vqs(vdev); + + return ret; +} + +/** + * viortc_remove() - remove a virtio_rtc virtio device + * @vdev: virtio device + */ +static void viortc_remove(struct virtio_device *vdev) +{ + /* In the future, PTP clocks will be deinitialized here. */ + + virtio_reset_device(vdev); + vdev->config->del_vqs(vdev); +} + +static unsigned int features[] = { + VIRTIO_RTC_F_READ_CROSS, +}; + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_CLOCK, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; +MODULE_DEVICE_TABLE(virtio, id_table); + +static struct virtio_driver virtio_rtc_drv = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .feature_table = features, + .feature_table_size = ARRAY_SIZE(features), + .id_table = id_table, + .probe = viortc_probe, + .remove = viortc_remove, +}; + +module_virtio_driver(virtio_rtc_drv); + +MODULE_DESCRIPTION("Virtio RTC driver"); +MODULE_AUTHOR("OpenSynergy GmbH"); +MODULE_LICENSE("GPL"); diff --git a/drivers/virtio/virtio_rtc_internal.h b/drivers/virtio/virtio_rtc_internal.h new file mode 100644 index 000000000000..c2b5387f506f --- /dev/null +++ b/drivers/virtio/virtio_rtc_internal.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * virtio_rtc internal interfaces + * + * Copyright (C) 2022-2023 OpenSynergy GmbH + */ + +#ifndef _VIRTIO_RTC_INTERNAL_H_ +#define _VIRTIO_RTC_INTERNAL_H_ + +#include + +/* driver core IFs */ + +struct viortc_dev; + +int viortc_read(struct viortc_dev *viortc, u64 vio_clk_id, u64 *reading); +int viortc_read_cross(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, + u64 *reading, u64 *cycles); +int viortc_cross_cap(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, + bool *supported); + +#endif /* _VIRTIO_RTC_INTERNAL_H_ */ diff --git a/include/uapi/linux/virtio_rtc.h b/include/uapi/linux/virtio_rtc.h new file mode 100644 index 000000000000..0926b3d58254 --- /dev/null +++ b/include/uapi/linux/virtio_rtc.h @@ -0,0 +1,159 @@ +/* SPDX-License-Identifier: ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* + * Copyright (C) 2022-2023 OpenSynergy GmbH + */ + +#ifndef _LINUX_VIRTIO_RTC_H +#define _LINUX_VIRTIO_RTC_H + +#include + +/* Device-specific features */ + +#define VIRTIO_RTC_F_READ_CROSS 0 + +/* readq message types */ + +#define VIRTIO_RTC_M_READ 0x0001 +#define VIRTIO_RTC_M_READ_CROSS 0x0002 + +/* controlq message types */ + +#define VIRTIO_RTC_M_CFG 0x1000 +#define VIRTIO_RTC_M_CLOCK_CAP 0x1001 +#define VIRTIO_RTC_M_CROSS_CAP 0x1002 + +/* Message headers */ + +/** common request header */ +struct virtio_rtc_req_head { + __le16 msg_type; + __u8 reserved[2]; +}; + +/** common response header */ +struct virtio_rtc_resp_head { +#define VIRTIO_RTC_S_OK 0 +#define VIRTIO_RTC_S_UNSUPP 1 +#define VIRTIO_RTC_S_NODEV 2 +#define VIRTIO_RTC_S_INVAL 3 +#define VIRTIO_RTC_S_DEVERR 4 + __u8 status; + __u8 reserved[3]; +}; + +/* readq messages */ + +/* VIRTIO_RTC_M_READ message */ + +struct virtio_rtc_req_read { + struct virtio_rtc_req_head head; + __u8 reserved[4]; + __le64 clock_id; +}; + +struct virtio_rtc_resp_read { + struct virtio_rtc_resp_head head; + __u8 reserved[4]; + __le64 clock_reading; +}; + +/* VIRTIO_RTC_M_READ_CROSS message */ + +struct virtio_rtc_req_read_cross { + struct virtio_rtc_req_head head; +/** Arm Generic Timer Virtual Count */ +#define VIRTIO_RTC_COUNTER_ARM_VIRT 0 +/** Arm Generic Timer Physical Count */ +#define VIRTIO_RTC_COUNTER_ARM_PHYS 1 +/** x86 Time Stamp Counter */ +#define VIRTIO_RTC_COUNTER_X86_TSC 2 + __le16 hw_counter; + __u8 reserved[2]; + __le64 clock_id; +}; + +struct virtio_rtc_resp_read_cross { + struct virtio_rtc_resp_head head; + __u8 reserved[4]; + __le64 clock_reading; + __le64 counter_cycles; +}; + +/** Union of request types for readq */ +union virtio_rtc_req_readq { + struct virtio_rtc_req_read read; + struct virtio_rtc_req_read_cross read_cross; +}; + +/** Union of response types for readq */ +union virtio_rtc_resp_readq { + struct virtio_rtc_resp_read read; + struct virtio_rtc_resp_read_cross read_cross; +}; + +/* controlq messages */ + +/* VIRTIO_RTC_M_CFG message */ + +struct virtio_rtc_req_cfg { + struct virtio_rtc_req_head head; + /* no request params */ + __u8 reserved[4]; +}; + +struct virtio_rtc_resp_cfg { + struct virtio_rtc_resp_head head; + /** # of clocks -> clock ids < num_clocks are valid */ + __le16 num_clocks; + __u8 reserved[10]; +}; + +/* VIRTIO_RTC_M_CLOCK_CAP message */ + +struct virtio_rtc_req_clock_cap { + struct virtio_rtc_req_head head; + __u8 reserved[4]; + __le64 clock_id; +}; + +struct virtio_rtc_resp_clock_cap { + struct virtio_rtc_resp_head head; +#define VIRTIO_RTC_CLOCK_UTC 0 +#define VIRTIO_RTC_CLOCK_TAI 1 +#define VIRTIO_RTC_CLOCK_MONO 2 + __le16 type; + __u8 reserved[10]; +}; + +/* VIRTIO_RTC_M_CROSS_CAP message */ + +struct virtio_rtc_req_cross_cap { + struct virtio_rtc_req_head head; + __le16 hw_counter; + __u8 reserved[2]; + __le64 clock_id; +}; + +struct virtio_rtc_resp_cross_cap { + struct virtio_rtc_resp_head head; +#define VIRTIO_RTC_FLAG_CROSS_CAP 0 + __u8 flags; + __u8 reserved[11]; +}; + +/** Union of request types for controlq */ +union virtio_rtc_req_controlq { + struct virtio_rtc_req_cfg cfg; + struct virtio_rtc_req_clock_cap clock_cap; + struct virtio_rtc_req_cross_cap cross_cap; +}; + +/** Union of response types for controlq */ +union virtio_rtc_resp_controlq { + struct virtio_rtc_resp_cfg cfg; + struct virtio_rtc_resp_clock_cap clock_cap; + struct virtio_rtc_resp_cross_cap cross_cap; +}; + +#endif /* _LINUX_VIRTIO_RTC_H */ From patchwork Fri Aug 18 01:20:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Hilber X-Patchwork-Id: 13357189 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B22C7657 for ; 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dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=opensynergy.com; Received-SPF: Pass (protection.outlook.com: domain of opensynergy.com designates 217.66.60.4 as permitted sender) receiver=protection.outlook.com; client-ip=217.66.60.4; helo=SR-MAIL-03.open-synergy.com; pr=C From: Peter Hilber To: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, virtio-dev@lists.oasis-open.org Cc: Peter Hilber , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Richard Cochran , netdev@vger.kernel.org, Marc Zyngier , Mark Rutland , Daniel Lezcano , Thomas Gleixner , linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v2 5/6] virtio_rtc: Add PTP clocks Date: Fri, 18 Aug 2023 03:20:11 +0200 Message-Id: <20230818012014.212155-6-peter.hilber@opensynergy.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230818012014.212155-1-peter.hilber@opensynergy.com> References: <20230818012014.212155-1-peter.hilber@opensynergy.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DB8EUR05FT051:EE_|BE1P281MB2918:EE_ X-MS-Office365-Filtering-Correlation-Id: 12ef3246-6da2-48cc-740e-08db9f894e81 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: E3W2IYB4VG9H86AGpHdVtKGDk9lLl9AJu6VjGL/gUYH/+qtLcFXVJapuwzlfxuFDqnfvGH3/KCeGLP42hzX54qWRoXEukEJAmpB75TiXfUo/Jo5XK+lVRui8IN7YaM4+LVEeOzbp02N5ccypxqXr+j0rEZ76BsHimuF55K3Qq4+WieddnqcBCMGZ6+/ue68IAYTxxKZWIt3S6N2aVY+6Iw6n9SkB1jVWa/dlcT8NNoS8nWSwYw30+9MoFmadRG4zmJHt5Nt/8A+A1AnyT6whQ8Z6BPrn6jys/bkXssIDdxGkT0S7fypEiVQlGbph7gZl5Vdz0EUxc1L4P1NwtpypOW2WK1VzbYqffhYslWOXMzI5FOvD4yCIwj1D2Hvu6lHPCsY/IXaF16UsNluxtaLZhy8XuyulzRobiVZkBMzevYal8/y2ypTDsScR6C5O72qm6KP/+NY8JdkzURRYxDph2xg+K5veV4zwX3z3LMkJrBk4rd/sSV/dnNB2tPBmYBPC+1TiCi0voFkETqTjMBIUQCBQrPYQPDzt8LsPjtoginpLC1p0eE4ZN3bxruilCwct00zXcjqxwoe6LMsKXciI0SajFR6eOgvvzAAx3HttcXLfuwT7ru24oQy5Pc7Q1cQNETGuxTgTOHAKggMBCNbOSiZXfFPE29LnpHWEiuAwTPVIJ6+u2K5+UzsLsEGCFJXoAhyXKomRaVj/JILASByBE+4c6kSoSLDhJCwDznaU7m1RHj1a+d8xYDzyQL1uYynYrnB7aqIrTB9xyxNn8aVmvFUZSYFkhMJjuh2/ySK/Ml7fDd3/DE51kxa/50zQ4AaA X-Forefront-Antispam-Report: CIP:217.66.60.4;CTRY:DE;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SR-MAIL-03.open-synergy.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230031)(346002)(376002)(396003)(136003)(39850400004)(451199024)(186009)(82310400011)(1800799009)(36840700001)(46966006)(8676002)(8936002)(4326008)(7416002)(70206006)(70586007)(42186006)(54906003)(30864003)(41300700001)(2616005)(40480700001)(26005)(12101799020)(44832011)(316002)(2906002)(5660300002)(478600001)(36756003)(36860700001)(47076005)(1076003)(83380400001)(82740400003)(81166007)(86362001)(336012)(36900700001);DIR:OUT;SFP:1102; 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Userspace should distinguish different clocks through the name assigned by the driver. A udev rule such as the following can be used to get a symlink /dev/ptp_virtio to the UTC clock: SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP UTC", SYMLINK += "ptp_virtio" The preferred PTP clock reading method is ioctl PTP_SYS_OFFSET_PRECISE2, through the ptp_clock_info.getcrosststamp() op. For now, PTP_SYS_OFFSET_PRECISE2 will return -EOPNOTSUPP through a weak function. PTP_SYS_OFFSET_PRECISE2 requires cross-timestamping support for specific clocksources, which will be added in the following. If the clocksource specific code is enabled, check that the Virtio RTC device supports the respective HW counter before obtaining an actual cross-timestamp from the Virtio device. The Virtio RTC device response time may be higher than the timekeeper seqcount increment interval. Therefore, obtain the cross-timestamp before calling get_device_system_crosststamp(). As a fallback, support the ioctl PTP_SYS_OFFSET_EXTENDED2 for all platforms. Assume that concurrency issues during PTP clock removal are avoided by the posix_clock framework. Kconfig recursive dependencies prevent virtio_rtc from implicitly enabling PTP_1588_CLOCK, therefore just warn the user if PTP_1588_CLOCK is not available. Since virtio_rtc should in the future also expose clocks as RTC class devices, it should make sense to not have VIRTIO_RTC depend on PTP_1588_CLOCK. Signed-off-by: Peter Hilber --- Notes: v2: - Depend on prerequisite patch series "treewide: Use clocksource id for get_device_system_crosststamp()". - Check clocksource id before sending crosststamp message to device. - Do not support multiple hardware counters at runtime any more, since distinction of Arm physical and virtual counter appears unneeded after discussion with Marc Zyngier. drivers/virtio/Kconfig | 16 ++ drivers/virtio/Makefile | 1 + drivers/virtio/virtio_rtc_driver.c | 111 ++++++++- drivers/virtio/virtio_rtc_internal.h | 48 ++++ drivers/virtio/virtio_rtc_ptp.c | 347 +++++++++++++++++++++++++++ 5 files changed, 520 insertions(+), 3 deletions(-) create mode 100644 drivers/virtio/virtio_rtc_ptp.c diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index e3dbf16fa977..7369ecd7dd01 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -187,4 +187,20 @@ config VIRTIO_RTC If unsure, say M. +comment "WARNING: The Virtio RTC driver is useless without VIRTIO_RTC_PTP." + depends on VIRTIO_RTC && !VIRTIO_RTC_PTP + +comment "Enable PTP_1588_CLOCK in order to enable VIRTIO_RTC_PTP." + depends on VIRTIO_RTC && PTP_1588_CLOCK=n + +config VIRTIO_RTC_PTP + bool "Virtio RTC PTP clocks" + default y + depends on VIRTIO_RTC && PTP_1588_CLOCK + help + This exposes any Virtio RTC clocks as PTP Hardware Clocks (PHCs) to + userspace. + + If unsure, say Y. + endif # VIRTIO_MENU diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index f760414ed6ab..4d48cbcae6bb 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -14,3 +14,4 @@ obj-$(CONFIG_VIRTIO_MEM) += virtio_mem.o obj-$(CONFIG_VIRTIO_DMA_SHARED_BUFFER) += virtio_dma_buf.o obj-$(CONFIG_VIRTIO_RTC) += virtio_rtc.o virtio_rtc-y := virtio_rtc_driver.o +virtio_rtc-$(CONFIG_VIRTIO_RTC_PTP) += virtio_rtc_ptp.o diff --git a/drivers/virtio/virtio_rtc_driver.c b/drivers/virtio/virtio_rtc_driver.c index 424500d2c4f7..3c11fa95b9a7 100644 --- a/drivers/virtio/virtio_rtc_driver.c +++ b/drivers/virtio/virtio_rtc_driver.c @@ -36,11 +36,16 @@ struct viortc_vq { * struct viortc_dev - virtio_rtc device data * @vdev: virtio device * @vqs: virtqueues + * @clocks_to_unregister: Clock references, which are only used during device + * removal. + * For other uses, there would be a race between device + * creation and setting the pointers here. * @num_clocks: # of virtio_rtc clocks */ struct viortc_dev { struct virtio_device *vdev; struct viortc_vq vqs[VIORTC_MAX_NR_QUEUES]; + struct viortc_ptp_clock **clocks_to_unregister; u16 num_clocks; }; @@ -588,6 +593,89 @@ int viortc_cross_cap(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, * init, deinit */ +/** + * viortc_init_clock() - init local representation of virtio_rtc clock (PHC) + * @viortc: device data + * @vio_clk_id: virtio_rtc clock id + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_init_clock(struct viortc_dev *viortc, u64 vio_clk_id) +{ + int ret; + u16 clock_type; + char ptp_clock_name[PTP_CLOCK_NAME_LEN]; + const char *type_name; + /* fit prefix + u16 in decimal */ + char type_name_buf[5 + 5 + 1]; + bool has_xtstamp_feature; + struct viortc_ptp_clock *vio_ptp; + struct virtio_device *vdev = viortc->vdev; + + ret = viortc_clock_cap(viortc, vio_clk_id, &clock_type); + if (ret) + return ret; + + switch (clock_type) { + case VIRTIO_RTC_CLOCK_UTC: + type_name = "UTC"; + break; + case VIRTIO_RTC_CLOCK_TAI: + type_name = "TAI"; + break; + case VIRTIO_RTC_CLOCK_MONO: + type_name = "monotonic"; + break; + default: + snprintf(type_name_buf, sizeof(type_name_buf), "type %hu", + clock_type); + type_name = type_name_buf; + } + + snprintf(ptp_clock_name, PTP_CLOCK_NAME_LEN, "Virtio PTP %s", + type_name); + + has_xtstamp_feature = virtio_has_feature(vdev, VIRTIO_RTC_F_READ_CROSS); + + vio_ptp = viortc_ptp_register(viortc, &vdev->dev, vio_clk_id, + ptp_clock_name, has_xtstamp_feature); + if (IS_ERR(vio_ptp)) { + dev_err(&vdev->dev, "failed to register PTP clock '%s'\n", + ptp_clock_name); + return PTR_ERR(vio_ptp); + } + + viortc->clocks_to_unregister[vio_clk_id] = vio_ptp; + + if (!vio_ptp) + dev_warn(&vdev->dev, "clock %llu is not exposed to userspace\n", + vio_clk_id); + + return 0; +} + +/** + * viortc_clocks_exit() - unregister PHCs + * @viortc: device data + */ +static void viortc_clocks_exit(struct viortc_dev *viortc) +{ + unsigned int i; + struct viortc_ptp_clock *vio_ptp; + + for (i = 0; i < viortc->num_clocks; i++) { + vio_ptp = viortc->clocks_to_unregister[i]; + + if (!vio_ptp) + continue; + + viortc->clocks_to_unregister[i] = NULL; + + WARN_ON(viortc_ptp_unregister(vio_ptp, &viortc->vdev->dev)); + } +} + /** * viortc_clocks_init() - init local representations of virtio_rtc clocks * @viortc: device data @@ -599,6 +687,7 @@ static int viortc_clocks_init(struct viortc_dev *viortc) { int ret; u16 num_clocks; + unsigned int i; ret = viortc_cfg(viortc, &num_clocks); if (ret) @@ -611,10 +700,24 @@ static int viortc_clocks_init(struct viortc_dev *viortc) viortc->num_clocks = num_clocks; - /* In the future, PTP clocks will be initialized here. */ - (void)viortc_clock_cap; + viortc->clocks_to_unregister = + devm_kcalloc(&viortc->vdev->dev, num_clocks, + sizeof(*viortc->clocks_to_unregister), GFP_KERNEL); + if (!viortc->clocks_to_unregister) + return -ENOMEM; + + for (i = 0; i < num_clocks; i++) { + ret = viortc_init_clock(viortc, i); + if (ret) + goto err_free_clocks; + } return 0; + +err_free_clocks: + viortc_clocks_exit(viortc); + + return ret; } /** @@ -703,7 +806,9 @@ static int viortc_probe(struct virtio_device *vdev) */ static void viortc_remove(struct virtio_device *vdev) { - /* In the future, PTP clocks will be deinitialized here. */ + struct viortc_dev *viortc = vdev->priv; + + viortc_clocks_exit(viortc); virtio_reset_device(vdev); vdev->config->del_vqs(vdev); diff --git a/drivers/virtio/virtio_rtc_internal.h b/drivers/virtio/virtio_rtc_internal.h index c2b5387f506f..ccf621a749da 100644 --- a/drivers/virtio/virtio_rtc_internal.h +++ b/drivers/virtio/virtio_rtc_internal.h @@ -9,6 +9,7 @@ #define _VIRTIO_RTC_INTERNAL_H_ #include +#include /* driver core IFs */ @@ -20,4 +21,51 @@ int viortc_read_cross(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, int viortc_cross_cap(struct viortc_dev *viortc, u64 vio_clk_id, u16 hw_counter, bool *supported); +/* PTP IFs */ + +struct viortc_ptp_clock; + +#if IS_ENABLED(CONFIG_VIRTIO_RTC_PTP) + +struct viortc_ptp_clock *viortc_ptp_register(struct viortc_dev *viortc, + struct device *parent_dev, + u64 vio_clk_id, + const char *ptp_clock_name, + bool try_enable_xtstamp); +int viortc_ptp_unregister(struct viortc_ptp_clock *vio_ptp, + struct device *parent_dev); + +#else + +static inline struct viortc_ptp_clock * +viortc_ptp_register(struct viortc_dev *viortc, struct device *parent_dev, + u64 vio_clk_id, const char *ptp_clock_name, + bool try_enable_xtstamp) +{ + return NULL; +} + +int viortc_ptp_unregister(struct viortc_ptp_clock *vio_ptp, + struct device *parent_dev) +{ + return -ENODEV; +} + +#endif + +/* HW counter IFs */ + +/** + * viortc_hw_xtstamp_params() - get HW-specific xtstamp params + * @hw_counter: virtio_rtc HW counter type + * @cs_id: clocksource id corresponding to hw_counter + * + * Gets the HW-specific xtstamp params. Returns an error if the driver cannot + * support xtstamp. + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +int viortc_hw_xtstamp_params(u16 *hw_counter, enum clocksource_ids *cs_id); + #endif /* _VIRTIO_RTC_INTERNAL_H_ */ diff --git a/drivers/virtio/virtio_rtc_ptp.c b/drivers/virtio/virtio_rtc_ptp.c new file mode 100644 index 000000000000..c79544d13a64 --- /dev/null +++ b/drivers/virtio/virtio_rtc_ptp.c @@ -0,0 +1,347 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Expose virtio_rtc clocks as PTP clocks. + * + * Copyright (C) 2022-2023 OpenSynergy GmbH + * + * Derived from ptp_kvm_common.c, virtual PTP 1588 clock for use with KVM + * guests. + * + * Copyright (C) 2017 Red Hat Inc. + */ + +#include +#include +#include + +#include + +#include "virtio_rtc_internal.h" + +/** + * struct viortc_ptp_clock - PTP clock abstraction + * @vio_clk_id: virtio_rtc clock id + * @ptp_clock: PTP clock handle + * @viortc: virtio_rtc device data + * @ptp_info: PTP clock description + * @have_cross: device supports crosststamp with available HW counter + */ +struct viortc_ptp_clock { + u64 vio_clk_id; + struct ptp_clock *ptp_clock; + struct viortc_dev *viortc; + struct ptp_clock_info ptp_info; + bool have_cross; +}; + +/** + * struct viortc_ptp_cross_ctx - context for get_device_system_crosststamp() + * @device_time: device clock reading + * @system_counterval: HW counter value at device_time + * + * Provides the already obtained crosststamp to get_device_system_crosststamp(). + */ +struct viortc_ptp_cross_ctx { + ktime_t device_time; + struct system_counterval_t system_counterval; +}; + +/* Weak functions in case get_device_system_crosststamp() is not supported */ + +int __weak viortc_hw_xtstamp_params(u16 *hw_counter, + enum clocksource_ids *cs_id) +{ + return -EOPNOTSUPP; +} + +/** + * viortc_ptp_get_time_fn() - callback for get_device_system_crosststamp() + * @device_time: device clock reading + * @system_counterval: HW counter value at device_time + * @ctx: context with already obtained crosststamp + * + * Return: zero (success). + */ +static int viortc_ptp_get_time_fn(ktime_t *device_time, + struct system_counterval_t *system_counterval, + void *ctx) +{ + struct viortc_ptp_cross_ctx *vio_ctx = ctx; + + *device_time = vio_ctx->device_time; + *system_counterval = vio_ctx->system_counterval; + + return 0; +} + +/** + * viortc_ptp_do_xtstamp() - get crosststamp from device + * @vio_ptp: virtio_rtc PTP clock + * @ctx: context for get_device_system_crosststamp() + * + * Reads HW-specific crosststamp from device. + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_ptp_do_xtstamp(struct viortc_ptp_clock *vio_ptp, + struct viortc_ptp_cross_ctx *ctx, + u16 hw_counter, enum clocksource_ids cs_id) +{ + u64 ns; + u64 max_ns; + int ret; + + ctx->system_counterval.cs_id = cs_id; + + ret = viortc_read_cross(vio_ptp->viortc, vio_ptp->vio_clk_id, + hw_counter, &ns, + &ctx->system_counterval.cycles); + if (ret) + return ret; + + max_ns = (u64)ktime_to_ns(KTIME_MAX); + if (ns > max_ns) + return -EINVAL; + + ctx->device_time = ns_to_ktime(ns); + + return 0; +} + +/* + * PTP clock operations + */ + +/** + * viortc_ptp_getcrosststamp() - PTP clock getcrosststamp op + * @vio_ptp: virtio_rtc PTP clock + * @xtstamp: crosststamp + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_ptp_getcrosststamp(struct ptp_clock_info *ptp, + struct system_device_crosststamp *xtstamp) +{ + struct viortc_ptp_clock *vio_ptp = + container_of(ptp, struct viortc_ptp_clock, ptp_info); + int ret; + struct system_time_snapshot history_begin; + struct viortc_ptp_cross_ctx ctx; + enum clocksource_ids cs_id; + u16 hw_counter; + + if (!vio_ptp->have_cross) + return -EOPNOTSUPP; + + ret = viortc_hw_xtstamp_params(&hw_counter, &cs_id); + if (ret) + return ret; + + ktime_get_snapshot(&history_begin); + if (history_begin.cs_id != cs_id) + return -EOPNOTSUPP; + + /* + * Getting the timestamp can take many milliseconds with a slow Virtio + * device. This is too long for viortc_ptp_get_time_fn() passed to + * get_device_system_crosststamp(), which has to usually return before + * the timekeeper seqcount increases (every tick or so). + * + * So, get the actual cross-timestamp first. + */ + ret = viortc_ptp_do_xtstamp(vio_ptp, &ctx, hw_counter, cs_id); + if (ret) + return ret; + + ret = get_device_system_crosststamp(viortc_ptp_get_time_fn, &ctx, + &history_begin, xtstamp); + if (ret) { + pr_debug("%s: get_device_system_crosststamp() returned %d\n", + __func__, ret); + } + + return ret; +} + +/** viortc_ptp_adjfine() - unsupported PTP clock adjfine op */ +static int viortc_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm) +{ + return -EOPNOTSUPP; +} + +/** viortc_ptp_adjtime() - unsupported PTP clock adjtime op */ +static int viortc_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta) +{ + return -EOPNOTSUPP; +} + +/** viortc_ptp_settime64() - unsupported PTP clock settime64 op */ +static int viortc_ptp_settime64(struct ptp_clock_info *ptp, + const struct timespec64 *ts) +{ + return -EOPNOTSUPP; +} + +/** + * viortc_ptp_gettimex64() - PTP clock gettimex64 op + * + * Context: Process context. + */ +static int viortc_ptp_gettimex64(struct ptp_clock_info *ptp, + struct timespec64 *ts, + struct ptp_system_timestamp *sts) +{ + struct viortc_ptp_clock *vio_ptp = + container_of(ptp, struct viortc_ptp_clock, ptp_info); + u64 ns; + int ret; + + ptp_read_system_prets(sts); + ret = viortc_read(vio_ptp->viortc, vio_ptp->vio_clk_id, &ns); + ptp_read_system_postts(sts); + + if (ret) + return ret; + + if (ns > (u64)S64_MAX) + return -EINVAL; + + *ts = ns_to_timespec64((s64)ns); + + return 0; +} + +/** viortc_ptp_enable() - unsupported PTP clock enable op */ +static int viortc_ptp_enable(struct ptp_clock_info *ptp, + struct ptp_clock_request *rq, int on) +{ + return -EOPNOTSUPP; +} + +/** + * viortc_ptp_info_template - ptp_clock_info template + * + * The .name member will be set for individual virtio_rtc PTP clocks. + */ +static const struct ptp_clock_info viortc_ptp_info_template = { + .owner = THIS_MODULE, + /* .name is set according to clock type */ + .adjfine = viortc_ptp_adjfine, + .adjtime = viortc_ptp_adjtime, + .gettimex64 = viortc_ptp_gettimex64, + .settime64 = viortc_ptp_settime64, + .enable = viortc_ptp_enable, + .getcrosststamp = viortc_ptp_getcrosststamp, +}; + +/** + * viortc_ptp_unregister() - PTP clock unregistering wrapper + * @vio_ptp: virtio_rtc PTP clock + * @parent_dev: parent device of PTP clock + * + * Return: Zero on success, negative error code otherwise. + */ +int viortc_ptp_unregister(struct viortc_ptp_clock *vio_ptp, + struct device *parent_dev) +{ + int ret = ptp_clock_unregister(vio_ptp->ptp_clock); + + if (!ret) + devm_kfree(parent_dev, vio_ptp); + + return ret; +} + +/** + * viortc_ptp_get_cross_cap() - get xtstamp support info from device + * @viortc: virtio_rtc device data + * @vio_ptp: virtio_rtc PTP clock abstraction + * + * Context: Process context. + * Return: Zero on success, negative error code otherwise. + */ +static int viortc_ptp_get_cross_cap(struct viortc_dev *viortc, + struct viortc_ptp_clock *vio_ptp) +{ + int ret; + enum clocksource_ids cs_id; + u16 hw_counter; + bool xtstamp_supported; + + ret = viortc_hw_xtstamp_params(&hw_counter, &cs_id); + if (ret) { + vio_ptp->have_cross = false; + return 0; + } + (void)cs_id; + + ret = viortc_cross_cap(viortc, vio_ptp->vio_clk_id, hw_counter, + &xtstamp_supported); + if (ret) + return ret; + + vio_ptp->have_cross = xtstamp_supported; + + return 0; +} + +/** + * viortc_ptp_register() - prepare and register PTP clock + * @viortc: virtio_rtc device data + * @parent_dev: parent device for PTP clock + * @vio_clk_id: id of virtio_rtc clock which backs PTP clock + * @ptp_clock_name: PTP clock name + * @try_enable_xtstamp: enable xtstamp op, if available + * + * Context: Process context. + * Return: Pointer on success, ERR_PTR() otherwise; NULL if PTP clock support + * not available. + */ +struct viortc_ptp_clock *viortc_ptp_register(struct viortc_dev *viortc, + struct device *parent_dev, + u64 vio_clk_id, + const char *ptp_clock_name, + bool try_enable_xtstamp) +{ + struct viortc_ptp_clock *vio_ptp; + struct ptp_clock *ptp_clock; + ssize_t len; + int ret; + + vio_ptp = devm_kzalloc(parent_dev, sizeof(*vio_ptp), GFP_KERNEL); + if (!vio_ptp) + return ERR_PTR(-ENOMEM); + + vio_ptp->viortc = viortc; + vio_ptp->vio_clk_id = vio_clk_id; + vio_ptp->ptp_info = viortc_ptp_info_template; + len = strscpy(vio_ptp->ptp_info.name, ptp_clock_name, + sizeof(vio_ptp->ptp_info.name)); + if (len < 0) { + ret = len; + goto err_free_dev; + } + + if (try_enable_xtstamp) { + ret = viortc_ptp_get_cross_cap(viortc, vio_ptp); + if (ret) + goto err_free_dev; + } + + ptp_clock = ptp_clock_register(&vio_ptp->ptp_info, parent_dev); + if (IS_ERR(ptp_clock)) + goto err_on_register; + + vio_ptp->ptp_clock = ptp_clock; + + return vio_ptp; + +err_on_register: + ret = PTR_ERR(ptp_clock); + +err_free_dev: + devm_kfree(parent_dev, vio_ptp); + return ERR_PTR(ret); +}